In the title compound, [Co(C(8)H(4)O(4))(C(5)H(8)N(2))(2)](n), each cobalt(II) ion is coordinated by two N and two O atoms in a distorted tetra-hedral geometry. The isophthalate ligands bridge the metal ions to form polymeric zigzag chains extending along the b axis. Weak C-H⋯O inter-actions contribute to the crystal packing stability.